The following background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
Generally, power plants that are or will be equipped with a carbon dioxide (also referred to as “CO2”) capture system use various configurations for the turbine/boiler steam cycle. One typical turbine cycle comprises high pressure, intermediate pressure, low pressure and boiler feedwater portions where low pressure steam is condensed separately from higher pressure steam. For instance, steam leaving the low pressure and boiler feedwater pump turbine is sent to a condenser to condense the steam, which can be recycled. Steam from another portion of the turbine cycle is condensed in a heat exchanger known as a reboiler and used to heat rich solvent to release CO2. Consequently, available heat from the low pressure steam is lost because the two steam condensing processes are distinct from one another.
In general, various processes for CO2 capture and steam cycle integration are known in the art. For example, U.S. Pat. Publ. No. 2007/0256559 to Chen et al. describes separating a gas from a gas stream emitted by a power plant, by injecting a low pressure steam from a turbine into a stripper. However, Chen's process of directly injecting steam into the stripper limits the applicability of Chen's process because the addition of water into the stripper can be undesirable depending on the solvent circuit used.
All publications herein are incorporated by reference to the same extent as if each individual publication or patent application were specifically and individually indicated to be incorporated by reference. Where a definition or use of a term in an incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply.
Thus, there is still a need for systems and methods of using turbine exhaust steam to heat rich solvent from a CO2 capture process.